7. Kernel Support for X

To make sure X support is enabled under NetBSD, the following
line must be in your config file in /sys/arch/i386/conf:

options XSERVER, UCONSOLE

7.1. Console drivers

The server supports the standard NetBSD/i386
console drivers: pccons, pcvt and wscons (in pcvt compatibility
mode). They are detected at runtime and no
configuration of the server itself is required.

The pccons driver is the most widely tested and is the console driver
contained in the NetBSD binary distribution's kernels.

The pcvt console driver was bundled with NetBSD until 1.4. The pcvt X
mode is compatible with the pccons driver X mode. It offers several
virtual consoles and international keyboard support. In order to use
this driver, change the line:

device pc0 at isa? port "IO_KBD" irq 1

to

device vt0 at isa? port "IO_KBD" irq 1

in your kernel config file, and rebuild and install your kernel.

Wscons is the current console driver, included in NetBSD 1.4 and
later. For now, XFree86 supports wscons using the pcvt compatibility
mode, so be sure to have the lines:

in your kernel configuration file if you're using wscons. Refer to the
wscons(4) and wsmouse(4) manual pages for
informations on how to configure wscons into the kernel.

7.2. Aperture Driver

By default NetBSD include the BSD 4.4 kernel security
feature that disable access to the /dev/mem device when in
multi-users mode. But XFree86 servers can take advantage (or require)
linear access to the display memory.

Most XFree86 4.4.0 card drivers require linear memory access.
There are two ways to allow XFree86 to access linear memory:

The first way is to disable the kernel security feature by adding
``option INSECURE'' in the kernel configuration file and build a new
kernel.

The second way is to install the aperture driver, included in source form in
xc/programs/Xserver/hw/xfree86/etc/apNetBSD.shar in the
XFree86 4.4.0 source distribution. Unpack it in a new directory of your
choice by running:

sh apNetBSD.shar

By default the aperture driver will be installed in
/usr/local/aperture. You can change this default directory by
editing Makefile.inc before building it.

Then run ``make build'' as root to install it. To enable it,
add the following line to /etc/lkm.conf:

Warning 1: if you boot another kernel than /netbsd,
loadable kernel modules can crash your system. Always boot in
single user mode when you want to run another kernel.

Warning 2: the aperture driver only allows one access at a time
(so that the system is in the same security state once X is
launched). This means that if you run multiple servers on multiples
VT, only the first one will have linear memory access.
Use ``option INSECURE'' if you need more that one X server at a time.